In this research, an evaluation system of aesthetics of landscape with bridge was developed by using artificial neural networks. The main results are as follows :1.For an arch bridge 43 evaluation items of aesthetics of landscape with bridge were considered, and then 20 items which affect aesthetics of landscape with bridge were determined by the use of the developed system. The neural network used in this system was trained successfully based on the results of questionnaires which were performed using 94 black-and-white photographs of arch bridges. Carrying out the sensitivity analysis, the effects of these 20 items on aesthetics of landscape with arch bridge were discussed.2.In order to consider the color effects on aesthetics of landscape with bridges, 25 pairs of color and black-and-white photographs of arch bridges were used for questionnaires. For an arch bridge 53 evaluation items including color effects were selected, and the neural network was trained successfully. The sensitivity analysis was carried our for both color and black-and-white photographs. It was clarified that the color effects strongly affect the aesthetics of landscape with bridge. 3.上記2.で評価した橋梁美(点数)を出力値(教師値),上記1.で選定した評価項目を入力値として,ニューラルネットワークにより学習させて,アーチ橋の景観評価システムを構築した。このシステムを用いて,橋梁美に影響を及ぼす評価項目の感度解析を行った結果,カラー写真とモノクロ写真では,影響を及ぼす項目がかなり異っており,色彩が橋梁美に及ぼす影響が大きいことがわかった。さらに,ここで構築した評価システムが,実際の橋梁景観設計へどのように適用できるかを,例を挙げて示し,本システムの有効性を明らかにした。